Warp stop motion for looms



Aug. 12, 1930. J.: NQRTHROP WARP 5T0? MOTION FOR Looms 3 Sheets-"Sheet 1 Riv/19701607" Filed Feb 18, 1929 Aug. 12, 1930. J. NORTHROP WARP STOP MOTION FOR LOOMS Filed Feb. 18, 1929 3 Sheets-Sheet 2 fivevzzbr M w 7 (WW we @519 M? Aug. 12, 1930. J. NORTHROP ,757

' WARP STOP MOTION FOR LOUIS Filed Feb. 18, 1929 3 Sheets-Sheet 3 Patented Aug. 12, 1939 FATENT Wi i JONAS NORTHROP, 0F HOPEDALE, MASSACHUSETTS, ASSIGNOR- TO STANDARD LOOMS, INCL, OF SPABTANBURG, SOUTH. CAROLINA, A CORPORATION OF SOUTH CAROLINA.

WAR]? STOP MOTION FOR LOOMS Application filed February 18, 1929.

The present invention relates to warp stop motions for looms.

The object of the present invention is to reorganize and improve warp stop motions for looms, and more particularly to provide a stop motion which is simple in construction and positive in operation, and which has provision for opening the warp to indicate the position of a fallen drop wire.

With this and other objects in view as will hereinafter appear, the present invention comprises the warp stop motion hereinafter described and particularly defined in the claims. 3

In the accompanying drawings, Fig. 1 is a side elevation of a loom with the improved warp stop motion applied thereto; Fig. 2 is a sectional elevation on line 2-2 of Fig. 4; Fig. 3 is a rear elevation of the warp stop motion; Fig. 4 is a plan view of the mechanism; Fig. 5 is a section on line 55 of Fig. 4; and Fig. 6 is a view similar to Fig. 5 but showing the parts in the position which they assume when a drop wire falls.

The illustrated embodiment of the invention comprises a warp stop motion in which the drop wires are supported as usual by the individual warp threads. The mechanism includes relatively movable transverse detector bars one of which is normally maintained stationary and the other of which is continuously reciprocated. The bars are adapted to be locked together in unison when a drop wire falls, and connections are provided whereby upon movement of the normally stationary detector bar, the shipper lever is actuated to knock off the loom. The movement of the detector bars after a drop wire has beenengaged by them serves to open the warp and thus to indicate the position of the broken warp. Provision is also made for assuring that knock-off occurs nearly at back center position of the lay when the shed is open and the shuttle is easily accessible.

Referring to the drawings, the loom has the usual frame 10, lay 12. lay sword 14, shipperlever 16, and knock-off lever 18, the shipper lever connecting with the link 20 to operate the usual clutch and brake mechanisms. The warp threads 22 individually support the Serial No. 340,805.

drop wires 24 which are of the usual construction, each having a hole 26 for receiving the thread and a longitudinal slot 28. The drop wires are arranged in one or more parallel sets across the loom, two of such sets being indicated in the drawings. Through the slots 28 of each set of drop wires extends a pair of detector bars consisting of a normally stationary detector bar 30 and a continuously reciprocating bar 82. The bars are provided with teeth 34. The two bars of each set are guided in channels 36 supported at opposite sides and at the center of the loom. In normal operation of the loom, the bar 32 is continuously reciprocated through the slots of the drop wires while the bar 30 remains stationary. Upon release of a drop wire through failure of a warp thread, the wire drops between the teeth, thereby locking the bars 30 and 32 together and causing them to be moved in unison. Four sets of bars are shown in the drawings, and accordingly four rows of drop wires may be accommodated. The number of drop wires actually used will be equal to the number of warp threads, and if the number of threads is not great, it may be unnecessary to employ the full capacity of the mechanism.

The mechanism by which the bars are ac tuated includes a bracket 38 in which is journaled a shaft 40. Secured to one end of the shaft is an arm 42 which is connected through a link 43 and a pitman rod 44 with an eccentric 45 on the cam shaft 46 of the loom. The cam shaft is driven from the crank shaft 47 by gears 48 and 49, constructed to drive the cam shaft one revolution for two revolutions of the crank shaft. Secured to the shaft is a drive member 50 which has four upstanding arms 52 each terminating in a yoke 54 to embrace a pin 56 on each of the positively driven detector bars 32. As the eccentric is continuously rotated, the drive member will be oscillated to reciprocate the detector bars 32. Each bar undergoes a complete reciprocation in one direction for each complete cycle of movement of the lay. As shown in Fig. 5, the drive member 50 is approximately at the limit of its left-hand travel, and it is adapted to oscillate between the position thus shown and a position on the other side of the center equally distant therefrom. The normally stationary bar 30 which lies in the channel 36 alongside the moving bar 32 is also provided with a pin indicated at 58 and this pin is employed to operate either one of the rocking actuators 60 and 62 whenever the bar 30 is moved in unison with the bar The actuator 60 comprises a web 63 to which are connected four upstanding arms 6d to ei'igage the corresponding nins 58 on one side thereof while the actuator 62 has the up standing arms 66 to engage the pins 58 on the opposite side. The actuators are provided respectively with hub portions 68 and 70 which are loosely received on the shaft 40. The hub portion 68 of the actuator 60 is formed at the bottom with a cam surface '2' 2 and the actuator 62 is similarly formed with a cam surface 7 1, both of which rest on a cam follower plate 7 6. The actuators 60 and 62 are normally imm vable so long as the warp threads support the drop wires, but one of them is moved from its center position whenever the bar 30 moves in one-direction or the other. The actuators 60 and 62 are maintained in an upright position and in engagement with the pin 58 by means of a spring 78.

The action which takes place when a warp thread breaks is illustrated in Fig. 6. The fallen drop wire is indicated at 2 L and the drive member 50 is shown as travelling in the direction of the arrow, it being assumed that the drop wire fell when the drive memberwas starting its left-hand movement from its extreme right-hand position. In moving to the position shown in Fig. 6, the pin 58 of the bar 30 has carried the actuator 60 away from its normal position, thus turning it on the shaft 4:0 and causing its cam surface 72 to depress the cam follower plate 76. If the wire had fallen while the drive member was moving in the opposite direction, the actuator 60 would have remained stationary and the actuator 62 would have been moved to the right. In either case, the cam follower is depressed by the movement of one or the other of the cam surfaces 72 or 74. Moreover, the movement of the bars in unison carries along the fallen drop wire, as shown in Fig. 6, thereby spreading open the warp and indicating the relative position of the broken thread.

The depression of the follower 7 6 is utilized to knock off the loom. To this end, the follower 76 is provided with a hub 80 which is journaled on a shaft 82. The follower is normally urged upwardly into engagement with the cams by a torsion spring 84. The hub 80 carries a depending arm 86 to which is adj ustably secured a wire link 88 by means of a bolt and slot connection 89. The wire is connected at the other end to a lifter 90.

The wire is formed with a coiled spring 92 between its points of connection to the link 86 and the lifter 90. The lift-er 90 comprises a bell crank pivoted at 98 on a bracket 94: attached to the loom frame and having at its outer end a cam surface 96 which engages the under side of a hunter arm 98. The bunter arm 98 is connected at its forward end to the knockoff lever 18 and is provided near the rear end with a striking shoulder 100 which is adapted to be engaged by a dagger 102 on the lay as the latter approaches back center. In normal operation, the striking shoulder 100 is inactively disposed below the path of movement of the dagger 102 but when the lifter is actuated, the shoulder is engaged by the dagger, thereby pulling the hunter arm rearwardly and oscillating the lever 18 to trip the shipper lever 16, thereby knocking off the loom.

A feature of importance comprises the arrangement whereby knock-oil not attained until the unison movement of the detector bars is suliicient to spread the warp by a predetermined amount. The drive member 50 oscillates equal distances both sides of the center position. The complete throw of the drive member from its extreme left-hand to its extreme right-hand position is preferably about an inch or slightly greater. It is desirable that after knock-oil, the fallen drop wire shall have moved. at least a half-inch, thus giving a suitable opening of the warp to indicate the position of the fallen wire. However, since the drop wire may fall at any time, it may happen that after a wire has fallen, the detector bars will have less than one-half an inch left to travel before completing their movement in one direction. This movement, however slight it may be, is sufiicient to oscillate either one actuator or the other and to depress the cam follower plate to some extent. However, the parts are preferably so adjusted that unless the unison movement of the bars is at least one-half inch, t e lifter 90 will not be operated sufficiently to )lace the strikin shoulder 100 in the path of the dagger 102. Knock-off, therefore, will not occur on the immediate rearward heat of the lay following detection of a broken warp. However, upon the next reciprocation of the detector bars in the opposite direction, a movement of one of the actuators at least one-half inch from the center position is assured, and the knock-off will therefore occur on the next succeeding rearward beat of the lay. The detector bars 32 are given a complete traverse in each direction for each complete cycle of movement of the lay. It is therefore assured that upon breakage of a warp, knock-off of the loom will occur either on the first or the next succeeding beat of the lay and in any case, at such a time that the fallen drop wire will have been moved at least one-half an inch. Adjustment of the amount of movement of the lifter is attained by the connection 89. The figure of one-half an inch is of course merely illustrative and the parts may be so arranged as to assure a warp opening of a greater or less amount. The spring 92 through which the link 86 is connected to the lifter 90 is a heavy spring, at least sufficiently heavy so that it is not stretched for small movements of the cam follower. Inasmuch as the lifter must be operated to lift the hunter into engagement with the dagger for movements of the detector bar ranging from one-half an inch to something over an inch, provision is made for yielding of the connection upon extreme throws of the bar such as might occur if a wire should be caught at the extreme limit of travel of the actuator as in Fig. 6.

The connections between the cam shaft and the crank shaft are so arranged that the detector bar completes its traverse in one direction or the other approximately as the lay reaches back center. This assures that knockoff will occur at the instant when the fallen drop wire has been given its maximum dis placement.

Inasmuch as a fallen drop wire is gripped with considerable force between the teeth of the detector bars, some dificulty might be experienced in releasing the drop wire. To permit convenient release, each of the actuators 60 and 62 is provided with a handle 110 by which the actuator and consequently the detector bar may be moved sufiiciently to relieve the grip on the drop wire.

A feature of importance resides in the construction of acenter support for the chan nels 36. As shown in Figs. 2 and 4, a set of guide pieces 112 extends transversely across the loom, these serving as means for separating and guiding the drop wires of the several rows and also as supports for the center bracket 11%. The bracket is received at the center of the loom on the guides 112 and is also attached to an angle bracket 116 which in turn is secured to the forward warp rest 118. The rear end of the bracket embraces the rear warp rest 120. The bracket has a plurality of upstanding supports 122 corre sponding in number to the number of channels 36 and being of a width approximately equal to the width of each channel. These supports are attached to the channels in any convenient manner as by a pin 12% upstanding from each support and received in a hole in the channel. Inasmuch as the width of each support 122 is less than the width of the longitudinal slot of the drop wire, it will be seen that if a drop wire falls near the center of the loom so that the movement of its lower end is impeded by the bracket, nevertheless the upper end of the drop wire is free to bend. Since the drop wires are of fairly flexible material, the length of fallen drop wire included between the top of the detector bar and the bottom of each support 122 is free to flex after the drop wire has been engaged between the teeth of the detector bars. It will be appreciated that without the narrow upstanding supports 122, the drop wire might be pushed by the unison movement of the detectors directly against a rigid abutting surface, consequently leading to damage to some of the parts.

7 It will be seen that'the warp stop motion of the present invention offers several advantages over those commonly in use. In thefirst place, it provides for opening of the warp to indicate the place of Warp failure, and to facilitate tying of the broken warp. Moreover, it is assured that knock-oil cannot occur until the warp has been opened by at least a predetermined amount. The loom knocks ofi' approximately at back center, when the shed is open and the shuttle is readily accessible.

Having thus described the invention, What is claimed is:

1. A warp stop motion having, in combination, drop wires, a pair of detector bars extending transversely across the loom, means for continuously reciprocating one of the detector bars including an oscillating shaft and a drive member connected thereto, the other detector bar being normally stationary but adapted to move in unison with the reciprocated detector bar when engaged by a fallen drop wire, a pair of opposed actuator members loosely mounted on the shaft and engagin with the normally stationary bar, means for moving one of the actuator members when the bars are moved in unison, and means operated upon movement of either one of the actuator members for knocking off the loom.

2. A. warp stop motion having, in combination, drop wires, a normally stationary cletector bar, a reciprocating detector bar, driving means for moving the reciprocating bar first in one direction and then the other for each complete cycle of movements of the lay, means on the bars for causing unison movement thereof when a drop wire falls, actuator members engaging with the normally stationary bar, means for moving one or the other of the actuator members depending upon the direction of unison movement of the bars, knock-oft connections, and means for causing knockoff if the unison movement is greater than a predetermined amount and for preventing knock-off until the next traverse of the bars if the initial unison movement is less than a predetermined amount.

3. A warp stop motion having, in combination, drop wires, a reciprocating detector bar, a normally stationary detector bar, an oscillating drive member for moving the reciprocating bar, a pair of opposed actuator members associated with the normally stationary bar, means on the bars to permit unison movement thereof when a drop wire falls, a pivotal mounting for the actuator members, means on the stationary bar engaging with the actuator members for moving one or the other thereof when the bar is moved, the actuator members having cam surfaces, a cam follower operated by either of the cam surfaces, and connections with the follower for knock-0E of the loom.

4;. A warp stop motion for looms having, in combination, a reciprocating detector bar, a normally stationary detector bar, a channel in which the bars are received, drop wires having slots through which the channels pass, and a center support for the channels having upstanding supporting legs of a sufficient height to permit flexing of the drop wires when the bars are moved in unison.

5. A warp stop motion for looms having, in combination, a continuously reciprocating detector bar, a normally stationary detector bar, a channel in which the bars are received, drop wires, teeth on the bars to permit the bars to move in unison when a drop wire falls, whereby the fallen drop wire opens the warp, and a support for the channels comprising a brackethaving upstanding legs engaging with the channels and of a width not greater than that of the channels, whereby a drop wire which falls near the support is permitted to flex.

In testimony whereof I have signed my name to this specification.

JONAS NORTHROP. 

